David Greenwalt (born October 16, 1949) is an American screenwriter, director, and producer.

He was the co-executive producer of the TV series Buffy the Vampire Slayer and co-creator of its spinoff, Angel. He is also co-creator of the short-lived cult television show Profit. He co-created the NBC supernatural drama Grimm.

Greenwalt was a co-executive producer on Buffy until the show's third season, when he was promoted to executive producer. He left the show at the end of the third season to co-create the spin-off series Angel with Joss Whedon. He was credited as a consulting producer on Buffy from Season 4 until the final season, although did not write or direct any episodes.

Greenwalt was an executive producer and served as the showrunner for the first three seasons. He left the staff at the end of the third season to pursue other works, and was credited as a consulting producer for the final two seasons. He returned in the fifth season to direct an episode.

On June 1, 2007, The Hollywood Reporter announced that he would serve as executive producer and showrunner on Moonlight, a similarly themed vampire detective show.[2] He later had to leave the show prior to its debut for health reasons, but executive producer Joel Silver stated that his imprint would remain: "He worked really hard on the arc of the series. He really helped us focus and get started."[3]

After he left Angel to do Jake 2.0, both shows ended up competing against each other on Wednesday nights at 9/8c on The WB and UPN respectively in the 2003–2004 season. Both series were cancelled at the end of that season.

In the Superman comic #180 Superman battles Dracula and in Dracula's "wine" cellar is a bottle of blood marked "Mr. David Greenwalt - 1949-1999". One of the contributors to the comic was Joss Whedon, who worked with David Greenwalt on Buffy the Vampire Slayer and Angel.